Natural convection melting in a high temperature flat plate latent heat storage system: Parameter study of enclosure dimensions

Kurzfassung

The impact of natural convection melting in a high temperature flat plate latent heat thermal energy storage system is studied numerically. The storage material is the eutectic mixture of sodium nitrate and potassium nitrate (KNO3-NaNO3). A parameter study on storage material enclosure dimensions is conducted for various widths and heights. Low to very high aspect ratios between 0.5 and 40 and Rayleigh numbers from 1.2·10^4 to 1.6·10^6 are obtained. The liquid phase fraction evolution with time is scaled to non-dimensional form and the impact of natural convection on the heat flux is shown with a convective enhancement factor that is the ratio of heat flux to a hypothetical heat flux only by conduction. The results can be used for future design optimizations considering the effect of natural convection.